Answer:
Oiling is done on a regular basis to sewing Machine because in the machine there are lots of machinery parts i.e. wheels and axels, etc. which are in continuous use and they possess so much frictional force between them that wear tear may be observed in those parts.
Most stores have 2 rows of aisles facing parallel to each other- wait, why are you even asking this question?
For that you have to use the Aufbau principle
For example, writing the electronic configuration of Fe(28)
I recommend that you memorize the aufbau principle. Once you learn it, you don’t need anything else except the atomic number of the element to write it’s electronic configuration.